Marine heatwaves under global warming
Marine heatwaves under global warming
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DOI：
10.1038/s41586-018-0383-9
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发表时间：
2018-08-16
期刊：
影响因子：
64.8
通讯作者：
Gruber, Nicolas
中科院分区：
文献类型：
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作者：
Frolicher, Thomas L.;Fischer, Erich M.;Gruber, Nicolas
海洋热浪（MHWs）是持续数天至数月（1）的极端温暖海面温度，可以延伸到数千公里（2）。最近观测到的一些海洋热浪显示，海洋生态系统（3 - 11）和渔业（12 - 14）极易受到这种极端气候事件的影响。然而，我们对过去发生的MHW（15）和未来发展的了解非常有限。在这里，我们使用卫星观测和一套地球系统模型模拟来表明，在过去的几十年里，MHW已经变得更持久，更频繁，更广泛和更强烈，并且这种趋势将在进一步的全球变暖下加速。在1982年至2016年期间，我们检测到MHW天数翻了一番，预计这一数字将进一步平均增加16倍，全球变暖1.5摄氏度相对于工业化前水平，全球变暖2.0摄氏度，23倍。然而，目前减少全球碳排放的国家政策预计到21世纪末将导致全球变暖约3.5摄氏度（16），为此，模型预测MHW的概率平均增加41倍。在这种变暖水平下，MHW的平均空间范围是工业化前的21倍，平均持续112天，最大海面温度异常强度为2.5摄氏度。预计最大的变化将发生在热带西太平洋和北冰洋。今天，87%的MHWs可归因于人类引起的变暖，在任何超过2摄氏度的全球变暖情景下，这一比例将增加到近100%。我们的研究结果表明，在全球变暖的情况下，MHWs将变得非常频繁和极端，可能会将海洋生物和生态系统推向其恢复能力的极限，甚至超越极限，这可能会导致不可逆转的变化。
Marine heatwaves (MHWs) are periods of extreme warm sea surface temperature that persist for days to months(1) and can extend up to thousands of kilometres(2). Some of the recently observed marine heatwaves revealed the high vulnerability of marine ecosystems(3-11) and fisheries(12-14) to such extreme climate events. Yet our knowledge about past occurrences(15) and the future progression of MHWs is very limited. Here we use satellite observations and a suite of Earth system model simulations to show that MHWs have already become longer-lasting and more frequent, extensive and intense in the past few decades, and that this trend will accelerate under further global warming. Between 1982 and 2016, we detect a doubling in the number of MHW days, and this number is projected to further increase on average by a factor of 16 for global warming of 1.5 degrees Celsius relative to preindustrial levels and by a factor of 23 for global warming of 2.0 degrees Celsius. However, current national policies for the reduction of global carbon emissions are predicted to result in global warming of about 3.5 degrees Celsius by the end of the twenty-first century(16), for which models project an average increase in the probability of MHWs by a factor of 41. At this level of warming, MHWs have an average spatial extent that is 21 times bigger than in preindustrial times, last on average 112 days and reach maximum sea surface temperature anomaly intensities of 2.5 degrees Celsius. The largest changes are projected to occur in the western tropical Pacific and Arctic oceans. Today, 87 per cent of MHWs are attributable to human-induced warming, with this ratio increasing to nearly 100 per cent under any global warming scenario exceeding 2 degrees Celsius. Our results suggest that MHWs will become very frequent and extreme under global warming, probably pushing marine organisms and ecosystems to the limits of their resilience and even beyond, which could cause irreversible changes.